Remove unused HTML attribute names
Remove unused HTML attribute names

Review URL: https://codereview.chromium.org/426873003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@179149 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs